Out of the 129 binaries we retrieved in the Milky Way, 94 have a secured HMXB identification. Of those, 80 have an unambiguous counterpart in Gaia EDR3. Since we are dealing with binary systems, the radial velocity (RV) measured by Gaia is unlikely to match the true systemic velocity. Hence we searched in the literature which of the HMXBs have a proper radial velocity follow-up using spectroscopy; only 25 have a measure of RV we can use. We made an exception of XTE J0421+560 (CI Cam) which has been determined to be seen pole-on [1]}; as such, we reckon we can use the RV measurement from [2]} for this HMXB, which pushes our sample size to 26 HMXBs. We present the astrometric data we retrieved for those 26 HMXBs in Table REF .
<TABLE>